clutch springs

[geeka]

Just turned my fire breathing 620 into a 750cc torgue Monster.  Good, bad, indiferent?  hugh clutch  slip at anything above 3000rpm in all gears above 3rd. 80mph in top pulling a measly 4,500 argh! I need stronger springs.  Ideas thanks.  Kurt

[Ddan]

The clutch shouldn't be slipping with the stock springs.  What oil are you using?

[Capo]

Theb clutch will handle in excess of 100hp with just 4 springs

[Duc Fever]

+1 doubtfull that it is the springs, maybe worn friction plates.

[brad black]

is it a 5 speed or 6 speed 620?  5 speed has a normal clutch, the 6 speed has the APTC clutch.

ime the 5 speed 620 has a fairly borderline clutch - we've had a few slip for no apparant reason.  i don't recall if the springs are different, but they must be to the 750.  the pack is the same # i'm sure.

from memory the 620 APTC has softer springs than the 800 APTC, so you could put s2r 800 springs into it.  even the s2r 800 springs are remarkably soft compared to the non APTC ones.

[A.duc.H.duc.]

I'd check out what Brad's saying, but my first thought is your plates are probably worn. It's possible they were borderline, and the extra torque of the big bore kit has pushed them beyond their limit. You can try deglazing them, or just get a new clutch pack.

Justin

[clubhousemotorsports]

We often had wet clutch race bikes that had this problem when you threw some more power at them. before buying new springs add some preload to your existing springs. The clutch pull will get a little harder but it usually solves the slipping.

[geeka]

Thanks folks.  Plates are fine. clutch is slipper.  Bought new springs, didnt fit probably a bad guess at the dealers.  Will try for springs again and adjustment.  Full synthetic I think Amsoil this time. Cheers.

[brad black]

by slipper you mean the std fitment APTC "applied torque" clutch?

from memory the APTC 620 springs are softer than the 800.  i think i checked this all out one time for a customers s2r 800.  barnett said they were looking at making some then - back in '05 or so.  these springs are much, much softer than non APTC springs.  you could fit 3 non APTC wet clutch springs if they go in and it'd never slip.

[truckinduc]

my plates were worn and i could slip it at 80mph in 6th gear. Im guessing thats your problem